/Engine/Source/Runtime/GeometryCore/Public/OrientedBoxTypes.h
Create a merged TOrientedBox, encompassing this box and one other. Uses heuristics to test a few possible orientations and pick the smallest-volume result. Not an optimal fit.
[TOrientedBox3](API\Runtime\GeometryCore\TOrientedBox3)< RealType > Merge ( const [TOrientedBox3](API\Runtime\GeometryCore\TOrientedBox3)< RealType > & Other, bool bOnlyConsiderExistingAxes ) const